/* * pfil_add_hook: add a function (hook) to the packet filter head. * The possible flags are: * * PFIL_IN call on incoming packets * PFIL_OUT call on outgoing packets * PFIL_ALL call on all of the above * PFIL_IFADDR call on interface reconfig (mbuf is ioctl #) * PFIL_IFNET call on interface attach/detach (mbuf is PFIL_IFNET_*) */